diff --git a/MasterFile/src/tests/test_debug_matches_release.cpp b/MasterFile/src/tests/test_debug_matches_release.cpp
index 87d62a3..eaeb737 100755
--- a/MasterFile/src/tests/test_debug_matches_release.cpp
+++ b/MasterFile/src/tests/test_debug_matches_release.cpp
@@ -79,7 +79,7 @@
             debug_output_enc + "\" \"" + debug_output_dec + "\"\" ";
 
         release_enc_cmd.insert(0, "\"\"");
-        release_enc_cmd + exe_input_debug + "\" compress \"" + input +
+        release_enc_cmd += exe_input_debug + "\" compress \"" + input +
             "\" \"" + release_output_enc + "\" 8 \"" + par_file_release +
             "\" 0\"";